The long-range research objectives of this laboratory are to better understand the mechanisms of metabolic control in mammalian tissues. The present study concerns the biochemistry and physiology of the kidney. We have developed an isolated perfused rat kidney preparation, and a variety of renal problems are being undertaken. Particular problems to be pursued are: 1) A study of factors regulating proximal sodium transport; 2) The relationship between overall renal sodium transport and oxygen utilization, and general determinations of oxygen consumption by the kidney; 3) Sites of action of certain diuretics; 4) The pathway of renal gluconeogenesis; 5) Various studies on the excretion, synthesis, metabolism, and action of cyclic in the kidney.